[azar1]

I think you're correct. They were distributing an iOS app outside of the approved channels, which is explicitly called out near the very top of the Apple Developer License Program agreement:

Applications developed under this Agreement for iOS Products, Apple Watch, or Apple TV can be distributed in four ways: (1) through the App Store, if selected by Apple, (2) through the B2B Program area of the App Store, if selected by Apple, (3) on a limited basis for use on Registered Devices (as defined below), and (4) for beta testing through TestFlight.